HEC: The Constellations of Exoplanets

Last Update: December 8, 2014

The stars with exoplanets are not equally distributed among the 88 astronomical constellations. Exoplanets detections are slightly biased toward the northern hemisphere and the sky area covered by each constellation is not equal. Many fall within the well known 12 zodiac constellations of the ecliptic that are associated with the astrological signs (Figure and Table 1). The night sky is full of stars with exoplanets (Figure and Table 2) but only some of those stars are visible to the naked-eye (Figure and Table 3). The actual EXOPLANETS ARE TOO DIM TO BE VISIBLE in any case, but it is just fun to identify their stars.

This page is part of an educational project for star parties about learning to locate the constellations and the stars with exoplanets. You can plan your observation night using free software such as Celestia or Stellarium, an online sky map, or a mobile app like Sky Map to locate the constellations and the stars listed in the figures and tables below (try to use the search feature by star name on your software of choice if available).

Figure 1. Number of stars with exoplanets in each zodiacal constellation, commonly known as astrological signs. Note that the astronomical name of the signs Scorpio and Capricorn are Scorpius and Capricornus, respectively, the rest have the same name as in astronomy. You can use this chart to brag that your astrological sign has more exoplanets than those of your friends, family, love, or dog. A great group conversation starter for your star party. Check Carl Sagan's opinion about astrology.

Table 1. List of the number of stars with exoplanets in each astrological sign as shown in figure 1.

Aries

Taurus

Gemini

Cancer

Leo

Virgo

Libra

Scorpio

Sagittarius

Capricorn

Aquarius

Pisces

7

10

9

8

15

26

3

27

25

5

14

39

Figure 2. Location of all 786 stars with 1,039 confirmed exoplanets (some stars have multiple planets). This plot provides a general sense of the distribution of these stars. You will need a star chart software for their accurate identification in the night sky. Only those with known distances within 100 light years are labeled. Click the image for a larger poster version. CREDIT: PHL @ UPR Arecibo and Jim Cornmell.

Table 2. List of constellations with their number of stars that have planets and total number of planets. Zodiac constellations are indicated with an asterisk. This list can be used together with a list of planet and star properties (i.e. PHL's Exoplanets Catalog) to plan educational observations. Some stars are even visible with the naked-eye (see Table 3). The constellations of Cetus and Ursa Major have more naked-eye visible stars with planets (5 in each).

ID — Number of the constellation.

Name — Name of the constellation.

Abb. — Abbreviated name of the constellation.

Stars — Number of stars with planets.

Planets — Total number of planets (some stars have more than one planet).

Density —Stars with planets per constellation area (stars/square deca-degrees).

HabPlanet — Number of potentially habitable planets in the constellation.

HabMoon — Number of planets with the potential for habitable moons in the constellation.

Visible — Number of stars that are visible to the naked eye down to 6 magnitude (not necessarily visible in city areas).

Note: NASA Kepler Mission observes the constellations of Cygnus, Lyra, and Draco. That explains the large number of stars with planets in these constellations.

Figure 3.Location of the 84 naked-eye visible stars (down to magnitude 6) with confirmed exoplanets (some stars have multiple planets). A star chart software is recommended to identify these stars in the night sky. Table 3 has some properties of these stars. Click the image for a larger poster version. CREDIT: PHL @ UPR Arecibo and Jim Cornmell.

Table 3. List of the 84 naked-eye visible stars with confirmed exoplanets down to magnitude 6. A clear and dark night, outside of city lights, is required for observing them (pick those below mag 3 if observing in the city). The list is sorted by constellation name. The brightest star with an exoplanet is HD 62509, better known as Pollux in the Gemini constellation. Tau Cet is the only star visible to the naked-eye with a potentially habitable exoplanet, but these planets are not confirmed yet.

Name — Name of the star.

Constellation — Name of the constellation.

Type — Star spectral type.

Mag — Visible magnitude of the star.

d — Distance to star (light years).

RA —Right Ascension (decimal hours).

DEC — Declination (decimal degrees).

Planets — Number of planets around the star, some have more than one.

HZ — Number of planets in the habitable zone. Most of them are big jovian planets.